Anthraquinone

• 9,10- dihydro- anthracene -9 ,10- dione
• 9,10- anthraquinone (IUPAC)

Rhombic, pale yellowish - green, odorless needles

Fixed

1.44 g · cm -3

286 ° C

380 ° C.

13 MPa (50 ° C)

• Very poor in water, poor in ethanol and diethyl ether
• Soluble in hot benzene

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Anthraquinone is a derived from anthracene quinone. It was first produced in 1836 by Auguste Laurent by oxidation of anthracene.

Occurrence

Anthraquinone comes in the form of the rare mineral Hoelit in nature. Anthraquinone derivatives are the active ingredients of various herbal laxatives: rhubarb root, buckthorn bark, cape aloe, senna and buckthorn berries.

Production and representation

Anthraquinone can be prepared by the oxidation of anthracene with nitric acid or chromic acid.

Conveniently, however, the reaction of benzene and phthalic anhydride by Friedel-Crafts. This initially results in a oxocarboxylic, then with sulfuric acid to anthraquinone further can be implemented.

Properties

Unlike most quinones, anthraquinone is not volatile in steam. However, compared to oxidizing agents is quite insensitive anthraquinone, by reducing agents easily in anthrahydroquinones or anthrone transferable. This reduction capacity is the basis for the linkage of anthraquinones to dianthrones and Polyanthronen. By introduction of functional groups into the molecule (e.g. hydroxy and amino groups ), especially in the positions 1, 4, 5 or 8, to increase the color intensity and the color changes. They can be selectively varied from yellow to purple.

Use

Anthraquinone is an important raw material for the production of anthraquinone dyes, eg alizarin. 2- alkyl anthraquinones ( e.g. 2- ethyl anthraquinone ) are used in the industrial production of hydrogen peroxide according to the anthraquinone process as a catalyst. Furthermore it is used as Vogelabschreckmittel.